Answer

Answer
Clicking the red button should always do the work, if it's not working try to reload the page and clicking it again. If it still does not work, try to clear cookies from your history.
This should automatically sign you off your account.

If you use the official client to run the game, please follow the procedures below.
- Uninstall the game client.
- Go to: %APPDATA%/../Roaming/TankiOnline
- Delete "Local Store" folder.
- Re-install the game client.
Customer support service by UserEcho
Clicking the red button should always do the work, if it's not working try to reload the page and clicking it again. If it still does not work, try to clear cookies from your history.
This should automatically sign you off your account.